This is more of a typical entry in the Dekalog template; we enter someone's life on a night, it's Christmas Eve, so when life is celebrated for its warm intimacy, but instead of the warmth of a house, we spend it outside in cold empty streets, chasing after phantoms from the past.
We begin with certainties of drama and have them broken down by the end. The man hasn't existed in her life for years. She has suffered the loneliness of both their absence and was on the brink that night, possibly brought back because he turned on the doorstep and went out in search of him. He could have brushed her off and stayed home with his family.
The most poignant shots are in the beginning and end. The beginning in the church where he turns around to see her, summoning or being summoned to look - Malick was in his European exile at the time, this is now his own vocabulary of ethereal swirl.
The ending is when he returns the morning after and tenderly finds his own wife asleep. Having experienced the brokenness of life on the long night, that you might help or not, here is the center of a life that lets you cultivate love.